by Ann » Thu Jul 29, 2021 6:59 am
Interestingly, Cygnus X-1 appears to be, well, relatively nearby. The Gaia parallax of the visible component, HD 226868, is 0.4218 milliarcseconds, according to Gaia. This translates as a distance of around 2370 light-years.
The Tulip Nebula, by contrast, is so very much further away, according to today's caption. The distance to the Tulip Nebula is said to be around 8,000 light-years. That doesn't look right, in my opinion, because I think the Tulip Nebula doesn't look as if it was 6,000 light-years further away than Cygnus X-1. And it would be very much of a coincidence if a remarkable high-mass binary with a black hole and an impressive nebula were seen right next to one another in the sky, but with a separation of 6,000 light-years between them.
(All right, all right, it happens that two remarkable deep-sky objects are seen next to one another in the sky, but with a separation between them of thousands of light-years. Michel Lakos' fine RGB picture of NGC 3603 and NGC 3576, the Statue of Liberty nebula, shows that the former is rather orange in color, whereas the Statue of Liberty nebula is more magenta. The orange color of NGC 3603 is an effect of dust reddening caused by a greater distance, and NGC 3603 is by far the more distant object of the two.)
Back to the Tulip Nebula and Cygnus X-1. Would you believe it, Simbad said that the parallax of the ionizing star of the Tulip Nebula, HD 227018, is 0.4750 milliarcseconds! Almost the same as the parallax of HD 226868, except it is a little larger, so that the ionizing star of the Tulip Nebula appears to be even closer! Its distance appears to be around 2,100 light-years!
Maybe it's time to abandon the idea that the Tulip Nebula is 8,000 light-years away?
Ann
Interestingly, Cygnus X-1 appears to be, well, relatively nearby. The Gaia parallax of the visible component, HD 226868, is 0.4218 milliarcseconds, according to Gaia. This translates as a distance of around 2370 light-years.
The Tulip Nebula, by contrast, is so very much further away, according to today's caption. The distance to the Tulip Nebula is said to be around 8,000 light-years. That doesn't look right, in my opinion, because I think the Tulip Nebula doesn't look as if it was 6,000 light-years further away than Cygnus X-1. And it would be very much of a coincidence if a remarkable high-mass binary with a black hole and an impressive nebula were seen right next to one another in the sky, but with a separation of 6,000 light-years between them.
[attachment=0]NGC 3603 and the Statue of Liberty Nebula.png[/attachment]
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(All right, all right, it happens that two remarkable deep-sky objects are seen next to one another in the sky, but with a separation between them of thousands of light-years. Michel Lakos' fine RGB picture of NGC 3603 and NGC 3576, the Statue of Liberty nebula, shows that the former is rather orange in color, whereas the Statue of Liberty nebula is more magenta. The orange color of NGC 3603 is an effect of dust reddening caused by a greater distance, and NGC 3603 is by far the more distant object of the two.)
Back to the Tulip Nebula and Cygnus X-1. Would you believe it, Simbad said that the parallax of the ionizing star of the Tulip Nebula, HD 227018, is 0.4750 milliarcseconds! Almost the same as the parallax of HD 226868, except it is a little larger, so that the ionizing star of the Tulip Nebula appears to be even closer! Its distance appears to be around 2,100 light-years!
Maybe it's time to abandon the idea that the Tulip Nebula is 8,000 light-years away?
Ann